The invention relates to a labeling machine having a revolving carrier on which at least one pickup member having an outwardly curved pickup surface for labels is rotatably mounted, and having a drive for each pickup member, said drive consisting of a fixed sun gear and a pinion meshing with the sun gear and displaceable axially in relation to the sun gear, the said pinion being coupled to the drive spindle of the pickup member by a cam-controlled compensating drive.
In a known labelling machine of this kind disclosed in U.S. Pat. No. 3,928,120, the compensating drive consists of a steep spiral between the pinion and the drive spindle of the pickup member. The cam control for the compensating drive consists of an axial cam member having a groove in which a cam follower member constructed as a roller is guided. The cam-controlled compensating drive brings about a result that, if the angular velocity of the carrier is constant, the angular velocity produced by the axial displacement of the pinion on the steep spiral is superimposed upon the constant angular velocity produced by the planetary drive, so that the rotatory movement of the pickup member is not regular but is accelerated and retarded. This acceleration and retardation of the pickup member is necessary in order to obtain at the various stations of the labelling machine, such as the label magazine, the glue roller and the labeling cylinder, a complete rolling of the cylindrically curved pickup surface of the pickup member mounted between the center of the curvature and the pickup surface.
The desired complete rolling of the pickup members on the label stack, and especially the rolling of the pickup member upon the transfer of the labels to the labeling cylinder is dependent upon the free play in the steep spiral and in the groove in the cam member as created by design or resulting from manufacturing tolerances. In the course of operation, such free play can increase to such an extent that a sufficient rolling action, especially at high outputs, is no longer assured.